CN109962030B

CN109962030B - Electrostatic chuck

Info

Publication number: CN109962030B
Application number: CN201711407089.3A
Authority: CN
Inventors: 黄允文; 连增迪; 吴狄
Original assignee: Advanced Micro Fabrication Equipment Inc Shanghai
Current assignee: Advanced Micro Fabrication Equipment Inc Shanghai
Priority date: 2017-12-22
Filing date: 2017-12-22
Publication date: 2022-03-29
Anticipated expiration: 2037-12-22
Also published as: CN109962030A

Abstract

The application provides an electrostatic chuck, central zone and marginal zone at the base set up the heat exchange passageway respectively, be provided with the isolation groove between central zone and marginal zone, the shape of isolation groove is cyclic annular, the isolation groove is close to the outer wall of marginal zone and is provided with the connector between the inner wall that is close to the central zone, the isolation groove can cut off central zone and marginal zone's heat transfer, realize the temperature difference in two regions, and simultaneously, because the existence of connector, play the effect of strengthening rib, when central zone and marginal zone's temperature difference is great, avoid because the too big base surface that leads to of stress warp to the epirelief.

Description

Electrostatic chuck

Technical Field

The application relates to the field of semiconductor manufacturing, in particular to an electrostatic chuck.

Background

In a semiconductor manufacturing process, an Electrostatic Chuck (ESC) is used to hold a wafer by Electrostatic force, so as to fix and support the wafer and prevent the wafer from moving or dislocating during a processing process. The electrostatic chuck comprises an upper ceramic material layer, a ceramic material is embedded with a direct current electrode, a metal base is arranged below the ceramic material layer, and the metal base is used for supporting the upper ceramic material layer and assisting in controlling the temperature of the upper ceramic material layer.

In order to improve the uniformity of the wafer processing process, at present, in some semiconductor devices, such as inductively coupled plasma devices, a dual-region electrostatic chuck is adopted, and a heat exchange channel is respectively arranged in a central region and an edge region of a base below the electrostatic chuck, so that heat conduction liquids with different temperatures can flow through the base, and thus, the purpose of adjusting the uniformity of the etching process can be achieved by respectively adjusting the temperatures of the central region and the edge region of the base.

For the electrostatic chuck with double-area temperature control, the metal base is isolated between the central area and the edge area through an isolation groove, and the isolation groove is of a hollow structure. However, in some applications, when the temperature difference between two sides of the central region of the electrostatic chuck is large (for example, greater than 30 degrees), due to the large thermal expansion coefficient of the metal, the metal expansion amplitude of the central region and the edge region also can generate a large difference, which can cause stress to concentrate on the isolation groove, further cause the upper surface of the base to be convex and deformed, affect the function of the electrostatic chuck above the metal base, and most seriously cause the very thin (several millimeters) ceramic material layer to be crushed and broken. Therefore, it is necessary to develop a new electrostatic chuck, which maintains the temperature difference adjustment range of the original multi-zone temperature control and also maintains the stability and reliability of the ceramic material layer above the electrostatic chuck without damage and deformation.

Disclosure of Invention

In view of the above, an object of the present invention is to provide an electrostatic chuck, which avoids the convex deformation of the base.

In order to achieve the above object, an embodiment of the present application provides an electrostatic chuck, which includes a ceramic material layer and a base for supporting the ceramic material layer, the base has a central region and an edge region, the central region and the edge region are respectively provided with a heat exchange channel, the edge region and the central region are provided with an isolation groove therebetween, the isolation groove is located in the base, the isolation groove is annular, a connector is provided between an outer wall of the isolation groove close to the edge region and an inner wall of the isolation groove close to the central region, and the connector is connected with the central region and the edge region.

Optionally, in the thickness direction of the electrostatic chuck, the connecting body is located in the middle of the isolation groove.

Optionally, the connecting body is a straight plate or an arc-shaped plate.

Optionally, the connecting bodies are a plurality of and are uniformly distributed.

Optionally, the thickness of the connecting body is smaller than the width of the isolation groove.

Optionally, the isolation groove is a circular ring concentric with the electrostatic chuck.

Optionally, the distance between the top surface of the connecting body and the top surface of the isolation groove and the distance between the bottom surface of the connecting body and the bottom surface of the isolation groove are at least 1 mm.

Optionally, the height between the top surface of the isolation groove and the top surface of the base ranges from 1mm to 3 mm.

Optionally, the connecting body, the central region and the edge region are of an integrally formed structure.

The embodiment of the application provides an electrostatic chuck, central zone and marginal zone at the base set up the heat exchange passageway respectively, be provided with the isolation groove in the base between central zone and marginal zone, the shape of isolation groove is cyclic annular, the isolation groove is close to the outer wall of marginal zone and is provided with the connector between two walls of the inner wall of central zone with being close to, the isolation groove can cut off central zone and marginal zone's heat transfer, realize that the temperature in two regions is different, and simultaneously, because the existence of connector, play the effect of strengthening rib, when central zone and marginal zone's temperature difference is great, avoid leading to the base surface to the upwards protruding deformation because the stress is too big.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1A illustrates a cross-sectional view of a base according to an embodiment of the present application;

FIG. 1 shows a horizontal cross-sectional view along AA1 in FIG. 1A;

FIG. 2A shows a cross-sectional view of a susceptor in the prior art;

FIG. 2 shows a horizontal cross-sectional view along AA1 in FIG. 2A;

FIG. 3 illustrates a partial cross-sectional view of a base according to an embodiment of the present application;

FIG. 4A illustrates a cross-sectional view of another susceptor in accordance with an embodiment of the present application;

fig. 4 shows a horizontal cross-sectional view along AA1 in fig. 4A.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, but the present application may be practiced in other ways than those described herein, and it will be apparent to those of ordinary skill in the art that the present application is not limited to the specific embodiments disclosed below.

As described in the background, in a semiconductor manufacturing process, an electrostatic chuck is a basic component of a manufacturing apparatus, which uses electrostatic force to hold a wafer, and plays a role in fixing and supporting the wafer, and preventing the wafer from moving or dislocating during the processing process, and has been widely used in semiconductor processes in plasma and vacuum environments, such as etching, chemical vapor deposition, ion implantation, and the like.

In order to improve the uniformity of the wafer processing technology, currently, in some semiconductor devices, such as inductively coupled plasma devices, a dual-region temperature-controlled electrostatic chuck is adopted, and a central region and an edge region of a metal base of the electrostatic chuck are respectively provided with a heat exchange channel for circulating heat conduction liquids with different temperatures, so that the purpose of adjusting the uniformity of the etching technology can be achieved by respectively adjusting the temperatures of the central region and the edge region of the base.

Referring to fig. 1A and fig. 1, there is shown a schematic structural diagram of a prior art susceptor, on which a ceramic material layer (not shown) is disposed, the susceptor including: a central area 100 and an edge area 200, said central area 100 and said edge area 200 each being provided with

heat exchanging channels

101, 201, an isolation groove 400 being provided between the edge area 200 and the central area 100. The isolation trench 400 is a hollow circular trench, that is, the isolation trench is located in the middle of the electrostatic chuck in the thickness direction of the electrostatic chuck. The heat conduction liquid with different temperatures can be introduced into the central area 100 and the edge area 200 to achieve the purpose of assisting in adjusting the uniformity of the manufacturing process of the central area and the edge area of the wafer, but because the temperatures of the two areas are different, the heat conduction between the two areas can be effectively blocked by arranging the hollow isolation groove 400, and the temperature independence of the two areas is ensured. But also concentrates the stress generated by the temperature difference between the two regions near the isolation trench 400, since the isolation trench 400 is a hollow structure, the region between the top surface of the isolation trench to the top surface of the base is generally thin, and the region where the heat transfer of the two regions is concentrated, so that the stress is concentrated on the region between the top surface of the isolation trench to the top surface of the electrostatic chuck, which is likely to cause the convex deformation of the top surface.

In view of the above problems, an embodiment of the present application provides an electrostatic chuck including a ceramic material layer (not shown) and a base for supporting the ceramic material layer, as shown in fig. 2A, a cross-sectional view of the base provided by the present application is provided, the base has a central region 100 and an edge region 200, the central region 100 and the edge region 200 are respectively provided with a

heat exchange channel

101, 201, an isolation groove 300 located in the base is provided between the edge region 200 and the central region 100, the isolation groove 300 is annular, a connection body 600 is provided between an outer wall of the isolation groove close to the edge region 200 and an inner wall of the isolation groove close to the central region 100, and the connection body 600 is connected with the central region and the edge region.

An electrostatic chuck is a device for holding a wafer by electrostatic force in a semiconductor manufacturing process, and generally includes a ceramic material layer (not shown) and a base for supporting the ceramic material layer, wherein the base is generally a metal block, and the material of the base may be aluminum, for example. In the embodiment of the present application, the

heat exchanging channels

101 and 201 of the central region 100 and the edge region 200, and the isolation trench are located in the susceptor, that is, the hollow structure of the entire susceptor is located in the middle of the entire susceptor in the thickness direction of the electrostatic chuck, and has a certain thickness from the top surface and the bottom surface of the susceptor. In a particular application, the heat exchange channels and the isolation slots may be integrally formed in the base.

In the embodiment of the present application, the susceptor includes a central region 100 and an edge region 200, as shown in fig. 2, a central region is inside a dotted line, an edge region is outside the dotted line, and both regions are formed with heat exchange channels, and heat conduction liquids with different temperatures can flow through the heat exchange channels, so as to adjust the temperatures of the central region 100 and the edge region 200, respectively, and achieve the purpose of adjusting the uniformity of the etching process.

The ranges of the central area 100 and the edge area 200 can be adjusted according to actual conditions, the heat exchange channel has an inlet end and an outlet end, the channel is a continuous flow channel from the outlet end to the inlet end, and the shape and the height-width ratio of the channel can be set according to specific needs, as shown in fig. 2, the shape of the channel can be, for example, a spiral shape, or a plurality of concentric circles which are communicated with each other, or a side-by-side channel which is connected end to end, and the like, under different shape settings, the total length of the heat exchange channel can be different, the longer the total length of the heat exchange channel is, the higher the heat exchange efficiency is, and the higher the heat exchange channel is, the wider the more the heat transfer liquid can flow on the cross section, the higher the heat exchange efficiency is. The shape and the like are provided here as examples, and do not affect the implementation of the embodiments of the present application, and the present application is not particularly limited to this. In addition, the heat transfer liquid may be, for example, a refrigerant or a heat medium fluid, and the heat transfer liquid may be a liquid having a larger specific heat capacity, which is advantageous for energy conservation.

In a specific application, the heat-exchange liquid can be introduced into the inlet end of the heat-exchange channel through the heat-exchange liquid supply pipeline (not shown), after circulating in the heat-exchange channel, the heat-exchange liquid flows out of the outlet end of the heat-exchange liquid supply pipeline, enters the cooling device (not shown), completes a thermal cycle, and after being cooled in the cooling device, the heat-exchange liquid enters the heat-exchange channel again, so that the temperature control of the electrostatic chuck is realized.

In order to solve the problem that the above stress is concentrated in the region between the top surface of the isolation groove and the top surface of the base, which causes the convex deformation of the top surface, in the base of the electrostatic chuck provided in the embodiment of the present application, the isolation groove 300 is configured to be annular, as shown in fig. 2, a connector is disposed between two walls of the isolation groove, and the connector is connected to the central region and the edge region. That is to say, the isolation groove is not a complete continuous annular hollow groove, the connector divides the isolation groove into a plurality of parts, the isolation groove does not run through on the two sides of the area where the connector is located, and the connector connected with the central area and the edge area is arranged in the isolation groove, so that the connector plays a role of a reinforcing rib and shares the stress generated by the heat exchange between the central area and the edge area, and the upward convex deformation of the surface of the base caused by the overlarge stress is avoided.

In a specific application, the shape of the isolation trench may be set according to the shape of the heat exchange channel in the center region and the edge region, for example, the isolation trench 300 may be a circular ring whose center coincides with the center of the electrostatic chuck. If the central region 100 is oval in shape, the corresponding isolation trench 300 may also be an oval ring. Of course, the isolation groove may be a ring shape having another shape, and the present application is not limited thereto.

In order to achieve a better heat insulation effect, and at the same time, the area between the top surface of the isolation groove and the top surface of the electrostatic chuck is not too thin, which causes the electrostatic chuck to be easily damaged, as shown in fig. 3, which is an enlarged view of a dotted frame portion in fig. 2A, the height d1 between the top surface of the isolation groove and the top surface 500 of the base may be in a range of 1-3 mm, and in actual operation, the height d1 may be adjusted as needed.

Can set up the thickness of connector 600 according to specific needs, the thickness direction of connector 600 is the isolation groove direction of encircling, and more preferably, the thickness of connector 600 is less than the width of isolation groove, like this, can effectively guarantee the isolation effect of isolation groove, plays the effect of strengthening rib simultaneously, when guaranteeing two regional temperature accurate control, avoids the base surface to face upwards protruding deformation.

The connector 600 is arranged in the isolation groove, the height of the connector can be set as required in the thickness direction of the electrostatic chuck, the connector can be completely blocked or partially blocked by the isolation grooves on two sides of the connector according to the connector with different heights, and the connector can be positioned at any position of the isolation groove when the height of the connector 600 is smaller than that of the isolation groove 300.

In a possible implementation manner of the present application, the connection body 600 may not completely separate the isolation groove 300, the isolation grooves are communicated at the upper and lower portions of the connection body 600, and the region where the connection body 600 is located partially blocks the isolation grooves and is connected to the inner region and the outer region, as shown in fig. 2A. Specifically, the connecting body 600 may be located at the middle position between the upper portion and the lower portion of the isolation groove 300, that is, in the thickness direction of the electrostatic chuck, the connecting body is located at the middle portion of the hollow groove, and each hollow groove is communicated with the upper portion and the lower portion of the connecting body 600 through air, for example, the distance d2 between the top surface of the connecting body and the top surface of the isolation groove is at least 1mm or more, and the distance d3 between the bottom surface of the connecting body 600 and the bottom surface of the isolation groove is at least 1mm or more, at this time, since the air in the middle of the isolation groove 300 can isolate the temperature, the isolation effect is better, and the connecting body has a reinforcing effect and a smaller heat conduction effect on the top of the base.

In another possible implementation of the present application, the upper or lower portion of the connection body 600 may be connected to the base, that is, the connection body completely blocks the isolation groove and connects to the inner region and the outer region. At this time, the isolation groove 300 still can achieve the purpose of isolating temperature, and at the same time, the connector 600 can share stress to reinforce the metal blocks around the isolation groove 300.

The number of the connecting bodies 600 may be one or more, and in the case of a plurality of connecting bodies, the connecting bodies may be uniformly distributed, that is, the connecting bodies are distributed at substantially the same height and at this height, the separation grooves are divided into a plurality of substantially equal portions. The uniformly distributed connectors are beneficial to more uniformly dispersing stress and better ensuring the smoothness of the electrostatic chuck.

In the embodiment of the present application, the structure of the connecting body may have any arrangement, and as shown in fig. 2 and 4, the connecting body may be, for example, a straight plate or an arc-shaped plate.

In one possible implementation manner of this embodiment, referring to fig. 2 and fig. 2A, the connecting body 600 is a straight plate, and the connecting body 600 transversely connects the inner wall and the outer wall of the isolation slot 300 to divide the isolation slot 300 into a plurality of parts, in this specific example, the length of the connecting body is substantially the same as the width of the annular isolation slot, the length direction of the connecting body is the extending direction of the connecting body between the two walls of the isolation slot, the connecting body 600 is connected between the two walls of the isolation slot 300 at the shortest distance, and the connecting body 600 is perpendicular to the tangent of the two walls of the isolation slot 300. In this case, the length of the isolation groove 300 is the shortest, and accordingly, the isolation effect on the temperatures of the central region 100 and the edge region 200 is good. Accordingly, the connection body 600 may completely separate the hollow grooves, may be connected to the metal block only at the upper portion or the lower portion, or may be present only at the middle portion of the isolation groove 300, and may be connected to the base only at the inner wall and the outer wall of the isolation groove 300.

In another possible implementation manner of this embodiment, the connection body 600 is an arc-shaped plate, as shown in fig. 4A and 4, in this specific example, the length of the connection body is greater than the width of the isolation groove, the connection body 600 may be connected between two walls of the isolation groove 300 at a longer distance, the connection body has an angle with a tangent of the two walls of the hollow groove, the angle is an acute angle or an obtuse angle, and the angle between each connection body 600 and the inner wall of the isolation groove 300 may be the same or different, and is not limited herein. In the present application, an angle in the range of 30-60 ° is preferred. In this case, the connecting body 600 is long and has a good supporting function for the base. Accordingly, the connection body 600 may completely separate the hollow grooves, may be connected to the metal block only at the upper or lower portion, or may be present in the middle portion of the isolation groove 300, and the connection portion with the metal block is only on the inner wall and the outer wall of the isolation groove 300.

Through the electrostatic chuck of this application embodiment, in the use, when base top surface central zone and marginal zone's temperature exceeded 30 ℃, the plane degree of whole base top surface still can keep within 0.1 mm.

The embodiment of the application provides an electrostatic chuck, central zone and marginal zone at the base set up the heat exchange passageway respectively, be provided with the isolation groove between central zone and marginal zone, the shape of isolation groove is cyclic annular, be provided with the connector between two walls of isolation groove, the isolation groove can cut off central zone and marginal zone's heat transfer, realize the temperature difference in two regions, and simultaneously, the connector can be consolidated the hollow groove, realize the effect of strengthening rib, when central zone and marginal zone's temperature difference is great, avoid because the base surface that the stress too big leads to the epirelief warp.

The foregoing is merely a preferred embodiment of the present application and, although the present application discloses the foregoing preferred embodiments, the present application is not limited thereto. Those skilled in the art can now make numerous possible variations and modifications to the disclosed embodiments, or modify equivalent embodiments, using the methods and techniques disclosed above, without departing from the scope of the claimed embodiments. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application still fall within the protection scope of the technical solution of the present application without departing from the content of the technical solution of the present application.

Claims

1. An electrostatic chuck comprises a ceramic material layer and a base for supporting the ceramic material layer, wherein the base is provided with a central area and an edge area, the central area and the edge area are respectively provided with a heat exchange channel, and an isolation groove positioned in the base is arranged between the edge area and the central area; the top surface of the isolation groove has a certain thickness from the top surface of the base; in the thickness direction of the electrostatic chuck, the connecting body is positioned in the middle of the isolation groove.

2. The electrostatic clamp of claim 1, wherein said connector is a straight plate or an arcuate plate.

3. The electrostatic chuck of claim 1, wherein said connecting member is a plurality of and uniformly distributed.

4. The electrostatic clamp of claim 1, wherein said connector has a thickness less than a width of said isolation slot.

5. The electrostatic chuck of claim 1, wherein said isolation groove is a circular ring concentric with said electrostatic chuck.

6. The electrostatic chuck of claim 1 wherein a distance of a top surface of said connecting body from a top surface of said isolation trench and a distance of a bottom surface of said connecting body from a bottom surface of said isolation trench are at least 1 mm.

7. The electrostatic chuck of claim 1, wherein a height between the top surface of the isolation trench and the top surface of the base ranges from 1mm to 3 mm.

8. The electrostatic clamp of claim 1, wherein said connector is a unitary structure with said central region and said edge region.